• Classification;
  • colloidal and surface chemistry;
  • pectin;
  • pectius;
  • precipitalis;
  • sucrose;
  • sugar juice;
  • zeta potential


Three pectins were isolated by 150 min extraction, at pH: 1, 3.5 and 8.5, from slices of fresh sugar-beet. Three precipitants (CaCl2, CuSO4and AlCl3&NaHCO3) were added to 100 cm3 of 0.1% solutions of pectins. CaCl2 and CuSO4 were applied as solutions (whose concentrations were: 0.76 g dm−3 and 0.5 g dm−3, respectively) and AlCl3&NaHCO3 was used as a powder of the proportion 1:1.04. Seven volumes of CaCl2 solution (ranging of 0.5–6.5 dm3) and seven volumes of CuSO4 solution (ranging of 0.5–6 dm3) were poured in flasks as well as eight quantities of AlCl3&NaHCO3 powder (ranging of 30–600 mg). Each precipitation process lasted for 10 h. The efficiency of precipitation was determined by measuring both the Zeta potential values and quantity of residual colloids after the precipitation. Optimal quantities of the applied precipitants were estimated as follows: 0.54% CaCl2, 0.24% CuSO4 and 0.64% AlCl3&NaHCO3 on sugar-beet, which is much lower than 1–3% CaO commonly used in everyday sugar production.